O-2
From Conservapedia
In the US Armed Forces, servicemembers pay grades and ranking are set by codes. Ranks are numbered from lowest to highest. There are several classifications, E (Enlisted), WO (Warrant Officer), CWO (Chief Warrant Officer), and O (Officer). O-2 is therefore the second lowest officer rank, being above an O-1 and below an O-3.
In the US Army, this would be a First Lieutenant and in the US Navy this would be a Lieutenant (j.g).
